X-ray ct apparatus and tube current determination method

An X-ray CT apparatus including an X-ray tube that performs X-ray exposure while rotating around an object, an X-ray detector that is disposed opposite the X-ray tube with the object interposed therebetween and detects the amount of X-rays transmitted through the object, an image reconstruction unit configured to reconstruct a tomographic image of the object on the basis of the amount of X-rays detected by the X-ray detector, and a display unit configured to display the tomographic image, the apparatus comprising:

• a receiving unit that receives an image noise standard deviation, which should be satisfied when imaging is performed by a specific imaging conditions in which a standard object having a predetermined size is imaged with a specific tube voltage, as a standard image quality level;
• a scan planning unit that calculates a target image quality level, which is a target image noise standard deviation, using the standard image quality level, calculates a scan tube current to achieve the target image quality level, and sets imaging conditions at the time of actual imaging using the scan tube current;
• and
• a control unit that controls operations of the X-ray tube, the X-ray detector, and the image reconstruction unit according to the set imaging conditions.